Combination of solid-state RF technology with another heat treatment for food

ABSTRACT

A line for heating, drying, disinfecting, pasteurizing and/or sterilizing a substance with an apparatus that includes at least one, preferably a multitude, solid-state radio frequency source(s) and a further heat treatment apparatus. A method for heating, drying, disinfecting, pasteurizing and/or sterilizing a substance with an apparatus that includes at least a solid-state RF energy source microwave heating step and a further heat treatment step.

FIELD

The present invention relates to a line for heating, drying, cooking,disinfecting, pasteurizing and/or sterilizing a substance with anapparatus comprising at least one, preferably a multitude, solid-stateradio frequency source(s) and a further heat treatment apparatus. Thepresent invention further relates to a method for heating, drying,cooking, disinfecting, pasteurizing and/or sterilizing a substance withan apparatus comprising at least a solid-state RF energy sourcemicrowave heating step and a further heat treatment step.

BACKGROUND

Treating substances by passing microwave radiation through thesubstances is common as well as in domestic as in industrialapplications. A conventional microwave oven for instance comprises amagnetron which produces the microwave energy. However, in industrialapplications wherein microwaves are generated by a magnetron the longoperating times will result in undesirable heat development and/or theprocess is not sufficiently reliable. Additionally, undesired hot spotsmay occur.

SUMMARY

It is therefore the objective of the present invention to provide aprocessing apparatus and a method that do not comprise the deficienciesaccording to the state in the art.

The problem is attained with a line for heating, drying, cooking,disinfecting, pasteurizing and/or sterilizing a substance with anapparatus comprising at least one, preferably a multitude, solid-stateradio frequency source(s) and a further heat treatment apparatus.

The disclosure made regarding this subject matter of the presentinvention also applies to the other invention and vice versa. Subjectmatters disclosed regarding this invention can also be combined withsubject matters from other inventions of the present application.

The present invention relates to a processing line with a solid-stateradio frequency (RF)-transistor(s) in a RF power amplifier. A radiofrequency power amplifier is an electronic amplifier, that converts alow power radio frequency signal into a higher power signal. Typically,RF-power amplifiers drive the antenna of a transmitter. The antenna canbe coupled to and/or located in a waveguide, wherein the antenna canradiate the microwaves into the waveguide which preferably is designedof reflective material and can guide the microwaves to a desiredlocation, for example into the product chamber wherein the substances tobe treated are located. Compared to a magnetron, an advantages of asolid-state RF energy technology is a low voltage drive, semiconductorreliability and lower energy consumption due to the advanced controlsystem. The inventive apparatus can be used to for example heat, cook,dry disinfect, pasteurize and/or sterilize a substance.

The substance is preferably an edible substance for human- and/oranimal-consumption, particularly protein containing food substance,particularly meat. The meat can be meat at a bone-structure, muscle meatand/or minced meat. In case the substance comprises a bone-structure,the bone structure is at least partially surrounded be the meat. Atypical example for a substance with a bone structure is a chicken-wing,a chicken-leg, a leg from a pig or a lamb and/or fish. The substance canalso be dough. The substance can also comprise at least parts of aninsect or a mixture of insects. Those insects are preferably suppliedalive to the inventive apparatus or line and are killed by microwaveradiation. In another embodiment already killed insects will bepreheated/precooked before the following processing step.

Transistor technology generates powerful RF fields. Preferably multipleRF sources will be applied, the sources can be controlled individuallyand preferably related to each other. For instance, in an applicationpumping a mass through a tube, gradually heating of the substance can beachieved by controlling the electromagnetic fields by controlling thepower level, frequency and phase versus time with such precision that aneven energy distribution will be achieved. In general, in case of achange in load in a certain spot of the substance, mass, substance flowor mass flow, the controller can control the specific parametersparameter in that certain spot in order to correct the adverse effectsof the load change. For instance, during cooking the load will changeconstantly, this change in load will be detected via the antenna bymeasuring the reflected energy. The control system will compare thetransmitted energy via the antenna with the reflected energy and willconsequently adjust the energy to be transmitted by the antenna. Forinstance, if no load is present within the product chamber, no energywill be absorbed, the antenna receives the reflected energy and thecontrol unit will stop transmitting new energy to the product chamber.With solid-state RF energy sources, the amplitude, the frequency, thephase versus time and/or the direction, and/or the total radiationenergy emitted can be controlled for each and every antenna. Such anadvanced energy management system based on a fast response to the heatdemand in certain spots of the substance(s) to be heated preventsdamaging of internal component and prevents an uncontrolled substancetreatment with uneven energy distribution. Due to the efficient use ofenergy resulting in less energy loss an additional advantage ofsolid-state RF energy sources is an increase in yield of substances tobe treated.

Additionally, according to the present invention, the line comprises afurther heat treatment apparatus. In this heat treatment apparatus, thesubstance is preferably further cooked, browned, fried, smoked and/orroasted. The further heat treatment apparatus may be, relative to theflow of the substances, upstream or downstream from the solid-stateradio frequency source(s)

A line according to the present invention comprises several treatmentsteps provided in a sequence. The substance is supplied to the line atits begin and is then transported continuously or semi-continuouslythrough the line until the end of the line, where the substance isdischarged and/or packaged. The transportation can be done by means of aconveyor, for example a belt, which connects the apparatus. Preferably,the line comprises a common control unit, which controls the individualapparatus as well as the handover of the substances from oneapparatus/step to the other.

According to a preferred embodiment of the present invention, theapparatus may not only comprise one but a multitude of solid-state radiofrequency sources. This can be accomplished by using one or moreantennas and/or one or more waveguides. Each radio frequency source canbe preferably powered individually and each radio frequency source canbe preferably controlled, more preferably closed loop controlled,individually. The frequency, the wavelength, the phase versus time, theamplitude, the direction of radiation and/or the overall magnitude ofthe radiated power can be controlled.

The solid-state radio frequency sources are preferably provided in anarray of n columns and m rows, wherein n is an integer >1 and m is aninteger ≥1. Preferably, the solid-state radio frequencies are arrangedequidistantly in one row and/or the columns are also arrangedequidistantly. In case a multitude of sources, they can be arranged atrandom.

Preferably, the solid-state radio frequency sources are providedequidistantly around the circumference of product chamber. In thischamber, the edible substance to be treated will be placed or it will betransported through this product chamber.

According to a preferred embodiment, each apparatus in the linecomprises an inlet and an outlet, which are spaced apart from eachother. The, preferably edible, substance enters each apparatus throughthe inlet, passes through the apparatus and then exits the apparatusthrough the exit which is preferably different from the inlet.

Preferably, each apparatus comprises means to transport the substancepast the treatment means of the apparatus, for example the solid-stateradio frequency source(s). These means can be a tube and a pump, whichpumps the substance through the tube. The tube is in the present casethe product chamber. Preferably, the tube is at least partially madefrom a material, that is at least partially transmittable, preferablytransparent for the RF-radiation. The tube can for example be made froma plastic material, preferably from a food grade plastic material. Thepump pumps the substance preferably as a continuous or semi-continuousstream past the RF-source(s). The speed at which the substance is pumpedis preferably adjustable, so that the residence time in the productchamber can be varied. The means can also be a conveyor, for example abelt, preferably an endless belt or an endless chain, wherein the chainis preferably not made from a metal material. The conveyor is preferablyat least partially transmittable for the RF-radiation. This conveyortransports the edible substance, preferably as individual portions, pastthe solid-state radio frequency source(s). The substances are preferablytransported continuously or intermittently by the conveyor. The speed ofthe conveyor is preferably adjustable, so that the residence time in theproduct chamber can be varied. Each apparatus of the line may have itsown conveyor means, particularly conveyor belt, which transports thesubstances through the respective apparatus.

At least some of the conveyors, preferably each conveyor, is adapted tothe specific requirements in the respective apparatus. The products arepreferably handed over from one conveyor to the other. At least one ofthe conveyors may comprise means to distribute and/or accumulate theproducts on the respective conveyor and more preferably according to theneeds of the specific treatment step.

Preferably, each processing apparatus and/or the line comprises acontrol system to control the individual apparatus, for example thesolid-state radio frequency source(s) and/or the transportation means.The control system preferably comprises one or more sensors, whosesignal(s) is used to control the parameters of one or more apparatus inorder to achieve desired treatment of the substance. Preferably, eachapparatus is controlled individually, but preferably by a common linecontrol system. Preferably one or more sensors are utilized to controlone or more solid-state radio frequency source(s), preferablyindividually and/or related to each other. For instance, in anapplication pumping a mass through a tube, gradually heating of the masscan be achieved by controlling the electromagnetic fields by controllingthe power level, frequency and/or phase versus time with such precisionthat, for example, an even energy distribution in the product chamber orin the substance will be achieved. The RF-energy load can be adapted tothe progress of the treatment process. For instance, during cooking theRF-energy load can change. This change in load can be detected, forexample via the antenna by measuring the reflected energy. The controlsystem will compare the transmitted energy via the antenna with thereflected energy and will consequently adjust the energy to betransmitted by the antenna. At each solid-state RF energy sources, theamplitude, the frequency, the wavelength, the phase versus time, and/ordirection of radiation can be controlled individually and/or in groups.The antenna may function as a sensor, for example to detect theradiation reflected from the substance to be treated.

The control system preferably controls at least one solid-state radiofrequency source such that it specifically heats the bone structure, inorder to specifically heat the meat surrounding the bone so that itreaches a temperature of at least 80° C., preferably at least 84° C.This preferred embodiment is particularly preferable in case the,solid-state radio frequency source(s) is used as a post heating step.

The sensor can sense one or more properties of the substance, forexample its temperature and/or the energy absorbed by the substance orpart of the substance, for example a bone-structure and/or the meatsurrounding a bone structure. One sensor can measure what kind ofradiation is reflected from the substance, for example the wavelength.The sensor can measure a temperature inside the substance, preferablythe core temperature and/or a temperature distribution within thesubstance. In case the substance is transported during its treatment,particularly with the RF-radiation, there can be multiple sensors alongthe transportation path. The local reading of the sensors can be used tocontrol the corresponding local treatment apparatus, for example thesolid-state radio frequency source(s) and/or the solid-state radiofrequency source(s) upstream and/or downstream from the respectivesensor.

The inventive food production line, preferably also comprises one ormore treatment apparatus upstream and/or downstream from the apparatuswith the solid-state radio frequency source(s), which change theconsistency, the shape and/or the surface of the substance, for examplea cutting-, grinding-, injection-, marinating-station, a formingstation, a batter-station and/or a marination-station. The stations canbe combined with conveyors. Preferably the substance enters the line atits entrance and then passes successively all stations of the respectiveline until it finally exits the line.

Preferably, the inventive line is provided downstream from a hopper inwhich, for example, a batch of an edible material is stored.

Preferably, one or more apparatus in the line, particularly theapparatus with the solid-state radio frequency source(s), can be atleast partially isolated from the ambient by one or more valves/gates.The substance, preferably the edible product, enters the respectiveapparatus, for example by means of a conveyor. Then the conveyor isstopped and a valve, like a gate is closed, preferably at the entranceand at the exit of the conveyor, so that, for example, no or littleradiation can exit from the apparatus to the ambient. After theRF-treatment, the valve/gate is reopened again and the treated substancecan exit the apparatus and preferably simultaneously untreated substanceenters the apparatus. The valve/gate can also be a feedthrough,particularly a rotary feedthrough, so that a continuous orsemi-continuous substance flow can be achieved.

Line according to the present invention preferably comprises:

-   -   a solid-state RF energy source microwave preheating step is        followed by a frying-step or vice versa and/or    -   a solid-state RF energy source microwave precooking step is        followed by a cooking-step or vice versa and/or    -   a solid-state RF energy source microwave drying step is followed        by a browning-step or vice versa and/or    -   solid-state RF energy source microwave drying step is followed        by a roasting-step and/or    -   solid-state RF energy source microwave drying step is followed        by a smoking-step or vice versa and/or    -   solid-state RF energy source microwave drying step is followed        by a radiation-step, such as infrared and grilling, or vice        versa and/or    -   a frying step is followed by a solid-state RF energy source        microwave precooking step, which is followed by a browning        and/or roasting and/or smoking and/or radiation step or in a        different sequence.

According to a preferred embodiment of the present invention, thesolid-state RF energy source(s) and the convection cooking means areprovided in one housing, preferably connected by conveyor means. Theconveyor means are preferably adapted to the needs during thesolid-state RF energy source microwave treatment step and the convectioncooking step. Alternatively, two successive conveyors are provided, eachadapted to the specific need of the solid-state RF energy sourcemicrowave treatment step and the convection cooking step.

Preferably, the line comprises means to measure the doneness of thesubstance. The doneness can, for example be determined by a temperatureat the core of the substance, at a bone-structure within the substanceand/or by determining a temperature distribution within the substance.The doneness can be determined for each substance or at random.Preferably, the measurement of the doneness is executed with thesolid-state RF energy source(s). The RF energy source(s) are preferablycontrolled based on such a measurement, for example to specifically heatthe at the core of the substance and/or at a bone-structure within thesubstance. In this case it is preferred that the RF energy source(s) isprovided downstream form a conventional heating step such as frying,roasting, browning or cooking.

Preferably, the substance comprises a bone-structure, wherein at leastone solid-state radio frequency source is controlled to specificallyheat the bone-structure and/or the meat surrounding the bone-structure.This can be for example carried out by controlling the frequency, thewavelength, the phase versus time, the amplitude, the direction ofradiation

and/or the overall magnitude of the radiated power of at least one RFenergy source such the specifically the bone structure and/or the meatsurrounding the bone structure are heated, so that their temperature isincreased fast, while preferably the other meat of the substance isheated less.

The problem is also solved with a method for heating, drying, cooking,disinfecting, pasteurizing and/or sterilizing a substance with anapparatus comprising at least a solid-state RF energy source microwaveheating step and a further heat treatment step.

The disclosure made regarding this subject matter of the presentinvention also applies to the other invention and vice versa. Subjectmatters disclosed regarding this invention can also be combined withsubject matters from other inventions of the present application.

The problem is furthermore solved with a method for heating, drying,cooking, disinfecting, pasteurizing and/or sterilizing a substance withan apparatus comprising a heat treatment step and a post heating with atleast a solid-state RF energy source microwave heating step.

The disclosure made regarding this subject matter of the presentinvention also applies to the other invention and vice versa. Subjectmatters disclosed regarding this invention can also be combined withsubject matters from other inventions of the present application.

The following disclosure applies to both inventive methods.

The substance to be treated can be an edible substance, for examplemeat, fish or dough. The fish and the meat may comprise abone-structure. The substance can also be an insect, which is, forexample, killed by the RF-radiation. In another embodiment alreadykilled insects will be preheated/precooked before the followingprocessing step.

Preferably the substance is transported from an inlet of a treatmentapparatus to an exit of the same apparatus which are spaced apart.

The substance can be transported continuously and/or intermittently.They can be transported as a string as an array or as individualportions.

Preferably one or more sensors are provided which measure one or moreproperties of the edible substance and/or the radiation reflected fromthe substance. The substance-properties are preferably measured at leasttwice during its treatment, preferably during its treatment withRF-radiation. The changes of the properties are determined and can betaken into account when controlling the solid-state radio frequencysource(s) and/or another apparatus in the line.

Preferably, the substance is heated, cooked, dried, disinfected and/orpasteurized, sterilized, fried, roasted, browned smoked and/or grilled.

At least one parameters of the substance to be treated are inputted intoa control system and that a control unit sets the parameters at leastfor the solid-state RF energy source microwave heating step accordingly.One example of a parameter is for example whether the substancecomprises a bone-structure and/or the size, preferably the average sizeof the bone-structure, or the volume of the bone structure, preferablyversus the volume of the surrounding meat.

Preferably, the substance comprises a bone-structure, wherein the postheating, i.e. the heating after a preheating step is adapted tospecifically heat the bone-structure. Preferably, the post heating iscarried out with RF-radiation and at least one solid-state RF energysource is controlled to specifically heat the bone structure or the meatsurrounding the bone structure. This can be carried out by controllingthe frequency, the wavelength, the phase versus time, the amplitude, thedirection of radiation and/or the overall magnitude of the radiatedpower to specifically heat the bone-structure and/or the surroundingmeat.

Preferably, at least one solid-state radio frequency source is utilizedto measure the doneness of the substance.

Preferably, the parameters of the further heat treatment step or thepost heating step are controlled by the control unit.

The problem is also solved with a method of treating a substancecontaining a bone structure, wherein the bone marrow is heated withmicrowaves generated by solid-state RF energy sources.

The disclosure made regarding this subject matter of the presentinvention also applies to the other invention and vice versa. Subjectmatters disclosed regarding this invention can also be combined withsubject matters from other inventions of the present application.

The following disclosure applies specifically to both inventive methodsand the inventive lines.

As an example, the chickens we consume today are between six and eightweeks old and have under developed more porous bones than olderchickens. When young chickens/broilers are frozen, liquids in the massof chicken including bone marrow will expand. The bone marrow inside ofchicken bones is purplish and can permeate through the porous chickenbones as it expands and forms ice crystals. These ice crystals furtherbreak down the bone structure. In case of heating products with bonessuch as chicken drumsticks, for instance after coating these products,the purple marrow in the bones seep through the porous bones and leaksinto the meat. The surface of the bones and the adjacent meat becomedeep red/purple or even black which is visible and unattractive. Firstcooking and then coat the food product with for instance batter resultsalso in leakage of bone marrow however the coating camouflages this.

Surprisingly, it has been found, that the leakage of bone marrow can bereduced or preferably stopped by coagulate the marrow within the bonesby using microwaves generated by solid-state RF energy sources. Thesettings such as power level, frequency, wavelength, phase versus time,amplitude, magnitude of radiated power and/or direction of radiationwill be optimized to penetrate the chicken meat, bone structure and totreat bone marrow. The treatment of substances comprising abone-structure with microwaves will be applied before the substances aresubjected to a heat treatment process such as frying and cooking,preferably the treatment will be applied before the fresh chickenbone-structure containing substances will be frozen. The process tominimize/stop leakage of marrow is not limited to chicken bone-structurecomprising substances but is also applicable for other bone-structurecontaining substances such as beef, lamb, pork, poultry in general.

Preferably the microwave heating is carried out prior to a heattreatment of the substance, preferably in an oven or a fryer, or priorto freezing of the substance.

The inventions are now explained according to the Figures. Theexplanations apply for all embodiments of the present inventionlikewise.

BRIEF DESCRIPTION OF THE DRAWINGS

The inventions are now explained according to FIGS. 1-32. Theseexplanations do not limit the scope of protection. The explanationapplies to all inventions likewise.

FIGS. 1a-1c, 2a-2c, 3a-3c, 4a-4b , and 5 each depict a heat treatmentline 1 comprising conveyor means.

FIGS. 6, 7, 8, 9, 10, and 11 each depict a heat treatment line and acomparison to the prior art.

FIG. 12 depicts a cooking apparatus.

FIG. 13a depicts a heat treatment line.

FIGS. 13b and 14 each depict a cooking apparatus.

FIGS. 15 and 16 each depict a heat treatment line with conveyor means.

FIGS. 17, 18, 19, 20, 21, 22, and 23 each depict a heat treatment with apost-heating with a solid-state RF energy source microwave.

FIGS. 24, 25, 26, 27, 28, and 29 each depict a line with a coatingapplication.

FIG. 30 depicts the inside of a microwave processing apparatus.

FIGS. 31a-32b each depict a line with an oven.

DETAILED DESCRIPTION

FIGS. 1a-1c depict a heat treatment apparatus 1 comprising conveyormeans 10, here an endless belt, running through a housing 8, here atunnel shaped housing, provided with an inlet 21 and an outlet 20, whichare separated from each other. The substances 11 is transported past atleast one, preferably a multiple, of solid-state RF energy sources 2.The housing 8 can extend in the transport direction around thesubstances 11 to be heat treated and/or around the conveyor means 10.The housing preferably comprises a slot at the inlet and at the outletfor the conveyor means 10. The housing 8 can be similar to a Faradaycage preventing electromagnetic waves coming out of the housing. Atleast the inner wall 9, but preferably the entire housing 8, can be madeof metal, preferably steel, for instance stainless steel to shield theelectromagnetic radiation. In a preferred embodiment, the housing 8comprises reflection- and/or absorption means at its inner surface to atleast partially eliminate radiation from external sources that entersthe housing through the inlet and/or the outlet and/or to preventradiation leaking via the inlet and/or outlet to the surrounding. Thereflection- and/or absorption means avoids that this electromagneticradiation reaches the antenna 17. The radiation from the multipleantennas preferably need not have to be shielded from each other.

The number of solid-state elements 2/antennas 17 preferably depends on,for instance, the required heating power, the width of the belt, thelength of the housing, the number and/or size and/or consistency ofsubstances 11, the position of the substances on the belt, the speed ofthe belt and/or the desired accuracy and/or speed of the heat treatmentprocess, particularly the uniformity of the heating process. FIGS. 1a-1cshow an embodiment with multiple solid-state elements 2/antennas 17positioned in each and every line of food substances. The substances 11,here provided in arrays, are transported continuously or intermittentlyfrom the inlet 21 to the outlet 20 and past the solid-state RF energysources 2, which emit microwaves, which heat the substances 11.Preferably, a multitude of rows, here five, of elements 2/antennas 17are provided along the path of the substances 11. The rows ofsolid-state elements 2/antennas 17 are provided preferably equidistantlyand/or each line comprises a multitude of solid-state elements2/antennas 17, which are preferably arranged perpendicular to line oftransportation of the substances 11. In each row, the solid-stateelements 2 are preferably arranged equidistantly. Each solid-stateelements 2 is preferably controlled individually and/or each solid-stateelement 2 or a group of solid-state elements 2/antennas 17 in one lineare controlled individually.

Regarding the embodiment of FIGS. 2a-2c , reference can be made to thedisclosure regarding FIGS. 1a-1c . FIGS. 2a-2c show an embodimentwherein the heat treatment apparatus 1 is provided with multiple, herethree solid-state elements 2/antennas 17, here above the substances andtwo in one of the two sidewalls of housing 8. In this example, thesubstances are arranged in an array and transported as an array past thesolid-state elements 2/antennas 17.

FIGS. 3a-3c depict an embodiment with randomly oriented substances onthe conveyor means 10. Otherwise, reference is made to disclosureregarding FIGS. 1a-1c and FIGS. 2a -2 c.

Regarding the embodiment according to FIGS. 4a-4b reference is made tothe disclosure according to the previous Figures. FIGS. 4a-4b depict across view and a detail of an embodiment of a solid-state RF energizedmicrowave apparatus. The solid-state energy sources 2 comprise awaveguide 16 and/or an antenna 17. The energy sources are preferably indirect contact with chamber 14 wherein the substances can be (pre)heatedand/or (pre)cooked. Preferably microwave transparent shielding means 23are provided to prevent pollution of the waveguide and antenna forexample with the food substance.

Regarding the embodiment according to FIG. 5 reference is made to thedisclosure according to the previous Figures. FIG. 5 depicts a crossview of an embodiment of a solid-state RF energized microwave apparatuswherein a cooling chamber 18 is provided which is connected to a coolingcircuit for instance a water cooling- and/or a gas-, preferably air-,cooling circuit. Shielding means 23 as depicted in FIGS. 4a-4b arepreferably provided to protect the solid-state element 2/antenna 17against the cooling medium. Despite this efficient energy managementadditional cooling of the waveguides and connected antennas may bedesirable in case of high energy output, for example during a longperiod of operation time. In another not depicted embodiment thesolid-state RF energy source can be cooled and/or its power supply. Thiscan be done per RF energy source 2 if needed. The cooling of thesolid-state RF energy source(s) is preferably controlled by atemperature measurement, which measures the temperature of one or moreof the RF energy source 2 and based on this reading controls a fluidflow of the cooling agent and/or its temperature.

FIG. 6 shows an inventive line and a comparison to the state in the art.FIG. 6 depicts a frying application wherein food substances are firstpreheated with solid-state RF energy sources till a predeterminedtemperature/value. Compare to the Prior-Art wherein no preheating takesplace, the residence time of the food substances in the fryer can beshorter; i.e. partial-frying instead of deep drying resulting in ashorter and cheaper fryer and less operating costs due to reduced oilvolume within the fryer. The food substance will absorb/pick-up less oildue to the shorter fryer time resulting in less fattier food substanceswith less calories and still coloured and crispy. In case the customerwants to maintain the same dimension fryer the addition of preheating bymicrowaves will result in a higher throughput/yield of food substances.

FIG. 7 shows an inventive line and a comparison to the state in the art.FIG. 7 depicts a cooking application wherein food substances areprecooked, preferably with minimum yield loss, with solid-state RFenergy sources until a predetermined temperature/value in the core or adesired temperature distribution in the substance has been reached.Compared to the prior-art wherein no precooking takes place, theresidence time of the food substances in the convection/steam oven canbe shorter resulting in a shorter/smaller and cheaper oven or a higherthroughput. In the embodiment according to FIG. 7 preferably only onecooking zone within the convection/steam oven is sufficient; in case ofa linear convection oven the oven can be shorter, in case of a spiralconvection oven provided with a double spiral layout, an oven providedwith a single spiral layout will be sufficient. In case the customerwants to maintain the same dimension of the oven the addition ofpreheating by microwaves will result in a higher throughput/yield offood substances.

FIG. 8 shows an inventive line and a comparison to the state in the art.An application used in the field of cooking is an oven with 2 zoneswhere in a first zone the food substances are dried, followed by asecond zone wherein the food substances are browned. FIG. 8 depicts suchthe inventive line or method wherein first the food substances are driedby microwaves generated by solid-state RF energy sources andsubsequently, the food substances are browned in a convection ovenprovided with preferably only one climate zone.

FIG. 9 depicts an inventive line and a comparison to the state in theart. FIG. 9 depicts an application wherein drying by microwavesgenerated by solid-state RF energy source(s) is followed by roasting ina convection oven,

FIG. 10 shows an inventive line and a comparison to the state in theart. FIG. 10 depicts an application wherein drying by microwavesgenerated by solid-state RF energy source(s) is followed by smoking withfor example natural gaseous smoke and/or liquid smoke in preferably acontinuous oven.

In applications depicted in FIG. 7-FIG. 10 are, based on cost efficientline solutions, after precooking the final cooking step performed inpreferably one climate zone. However, the invention is not limited tothe use of only one climate zone after precooking the food substances.

FIG. 11 shows an inventive line. FIG. 11 depicts an application directedto preferably coated food substances for instance battered and breadedmeat substances. Depending on the type of coating, to avoid damage ofthe coating the food substances should be dropped directly into an oilbath and should be fried for at least several seconds. In case ofnon-buoyant food substances, a Teflon belt can be provided within thefryer to prevent sticking of the coating/coated substances to the belt.This frying process with only very short frying time will set thecoating such that it will be less vulnerable and that the coatedsubstances are able to be further transported on conveyor means 10 to amicrowave precooking apparatus to precook the substances and finally toan oven, preferably a convection oven, to brown the food substances.

In an embodiment of the invention the temperature of food substances 11spread across the width of the conveyor means 10 is measured and in caseof deviating temperatures of the substances, the difference will atleast partially be equalized. Reference can be made to FIG. 1a to FIG.5. The solid-state energy sources will transmit energy towards the foodsubstances and will be able to detect how much energy will be reflected.Based on this measurement, a control unit can calculate how much energyis absorbed by the food substances. Depending on thismeasurement-result, the temperature of the individual food substanceswhich are below a predetermined temperature range can beadjust/increased by directing microwave energy to these individualsubstances.

In a preferred embodiment of the invention a heat treatment linecomprises a multitude of heat treatment apparatus including at least onemicrowave heating apparatus, wherein the microwaves are generated bysolid-state RF energy sources. Other apparatus in this heat treatmentline are for instance a deep fat fryer, a convection cooking heatingapparatus and/or a steaming apparatus. For example, precooking takesplace in a linear microwave oven and final cooking takes place in asingle spiral oven.

In another embodiment, the function of multiple separate heatingapparatus will be combined in one or more heating apparatus. Forinstance, a single heat treatment apparatus is provided with microwaveheating means generated by solid-state RF energy sources in one zone andconvection heating means in one or more other zones. FIG. 12 depictssuch a, preferably linear, oven wherein a first zone to precook foodsubstances with microwaves generated by solid-state RF energy sources.Depending on the dewpoint in the second zone condensation cooking and/orconvection cooking will take place. The dewpoint within the secondzone/cooking chamber during cooking can be adjusted, therefor the ovencan be provided with at least one fan, at least one heating element, atleast one fluid supply, preferably a steam or water supply and/or atleast one fresh air supply. The food substances will be heated by a hotair/fluid forced over the surface of the food substance.

In a further embodiment solid-state RF energy sources to generatemicrowave heating will be provided within one or more cookingchambers/zones combined with one or more other heating means. Aim ofthis inventive application is to end up with the desired texture,taste/bite, moisture content, appearance and color of the resultingsubstance in a relatively short period of time by a combination ofsimultaneously running heat treatment processes in one and the samecooking chamber/zone such as a combination of microwave heatinggenerated by solid-state RF energy sources and convection heating. Incase multiple climate zones are needed, the oven will be provided withmultiple cooking chambers/climate zones and each and every chamber/zonecan be provided with multiple heating means resulting in an extension ofthe scope of substance and process applications.

Preferably, the processing apparatus and/or the inventive line comprisesa control system to control the solid-state radio frequency sources. Thecontrol system preferably comprises one or more sensing means, whosesignal(s) is used to control one or more solid-state radio frequencysource(s), preferably individually and/or related to each other. Forinstance, in an application transporting substances over a continuousrunning belt, gradually heating of the substances can be achieved bycontrolling the electromagnetic fields by controlling the frequency, thewavelength, the phase versus time, the amplitude, the direction ofradiation and/or the overall magnitude of the radiated power. The phaseof the signal from one or more solid-state RF energy sources can beshifted relative to the others which will change the energy distributionwithin the cooking chamber. This with such precision that, for example,an even energy distribution in the product chamber or in the substancewill be achieved. Other parameters influencing the heat treatment offood substances are type of food, weight, temperature, moisture contentand parameters related to the processing apparatus such as heatingpower. During heat treatment of food substances parameters such astemperature and moisture content will change and therefore multiplemeasurements should be done in the course of the process. Consequently,the control unit will take these measurements into account whencontrolling the solid-state radio frequency sources. The closed-loopcontrol system will use the feedback information of the sensing means toselect the timing or the heat sources, the power of the heat sources andthe climate in the oven such that the cooking of the substances will beoptimized.

In a preferred embodiment of the invention the solid-state RF energyload can be adapted to the progress of the treatment process. Forinstance, during cooking the solid-state RF energy load can change. Thischange in load can be detected, for example via the antenna 17 bymeasuring the reflected energy. The control system will compare thetransmitted energy via the antenna with the reflected energy and willconsequently adjust the energy to be transmitted by the antenna. At eachsolid-state RF energy source, the frequency, the wavelength, the phaseversus time, the amplitude, the direction of radiation

and/or the overall magnitude of the radiated power can be controlledindividually and/or in groups. The antenna may function as a sensor, forexample to detect the radiation reflected from the substance to betreated. With this information the control unit can determine to whichspots in the substance more or less energy should be radiate such that,in case of preheating/precooking food substances, within certaintolerances, an equal temperature of all substances can be achieved byadjusting the signals to each solid-state RF energy source. In this waycold spots and hot spots in the food substance, typical to an ovenwherein microwaves are generated by a magnetron, will be avoided.Multiple antennas can be provided in order to increase the effectivenessof the control system and the antennas can be positioned in differentplanes and/or positions along the movement path of the food substances.

In a further embodiment of the invention the energy absorbed by thesubstance can be measured (absorption measurement) and via an algorithmcan be detected what the doneness of the food substance is, in whatstage the cooking process is and this will be the base to determine tofinish the cooking process to reduce/prevent cooking losses and toprevent that the food substances will be overcooked.

FIG. 13a depicts the embodiment of FIG. 11 extended with measurementmeans M such as solid-state RF sources to measure the doneness and/orstatus of the food substances between individual heat treatments.Preferably the doneness measurement will be the base for controlling theprevious and/or following heat treatment processes.

FIG. 13b depicts a, preferably linear, oven with a first zone to precookfood substances with microwaves generated by solid-state RF energysources and a second zone for convection cooking. Compare to theembodiment in FIG. 12 a measurement zone is arranged in or after thesecond zone wherein for instance solid-state RF energy sources areprovided in order to measure the doneness of the food substances.Preferably, the humidity in this area is such that a reliablemeasurement can take place. After or during measurement of the doneness,final cooking of the food substances will take place and cookingparameters will be via the control unit based on measurements done inthe measurement zone.

FIG. 14 depicts an embodiment of a two chamber/zone spiral cooking ovenas known in the field such as the GEA CookStar wherein in the first zonethe food substances will be heated with condensation cooking and in asecond zone the food substances will be finally cooked by convectioncooking. Such cooking process will be used for instance for cookinguncooked chicken pieces. Preferably, measurement means M such asmicrowave solid-state RF sources are provided between both zones, notfor heating up the food substances, but to be able to measure thedoneness and/or the status after heat treatment in the first cookingchamber/zone. Preferably, the climate in the measurement zone is suchthat a reliable measurement can take place. Further measurement means Msuch as solid-state RF sources 2 are preferably provided before theentrance 21 of the oven and after the outlet 20 of the oven. In a morepreferred embodiment also measurement means such as solid-state RFsources 2 are provided within zone one and within zone two. The feedbackof all the measurement means will be used to control the heat treatmentprocesses. This embodiment is not limited to condensation cooking in thefirst zone but the combination of condensation and convection cookingand an eventual additional impingement zone is applicable too.

In one embodiment detection means 25 such as a camera can be provided tobe able to detect/identify the position and/or type and/or volume and/orcolor of the food substance/mass. Therefor the detection means ispreferably positioned at the entrance of the apparatus. Furtherdownstream in the apparatus detection means can be provided todetect/identify the status of the heating process and as a result of theimages the control unit can adjust the heating process. More preferablythe detection means and relating software will be used able to handleconveyor means with multiple lines with substances but also be able tohandle conveyor means with random oriented food substances. The controlunit is able to determine at which time which energy source will beactivated based on amongst others the speed of the conveyor 10. In casefor instance the volume and type of the food substances is determinedthe control unit is able to calculate the heat treatment processparameters.

For all above mentioned embodiments, a control system can be provided tobe able to introduce pre-programmed cooking menus/recipes. Basicparameters for the menus/recipes are for instance belt load and/or speedof the conveyor means. Input parameters in the cooking menu/recipe basedon cooking with microwaves are for instance temperature of thesubstance, size of the food substance, weight substance, moisturecontent substance and food type. With the set of parameters, the controlunit can determine the cooking parameters such as temperature and timeand is able to (pre)heat/((pre)cook the food substances. However,manually input of these cooking parameters will also be possible andwithin certain ranges the control can optimize the manual inputtedvalues depending on the substance parameters and the running cookingprocess.

In case of a combination oven input parameters will also be related toother heat sources. For instance in a combination oven comprisingsolid-state RF energy sources and convection cooking means, inputparameters such as temperature hot air, humidity, fan speed, flowrateprocess fluid, time and pressure can also be part of the cooking menu.

Final cooking of food substances with only microwaves can result in anundesired texture, taste/bite, moisture content, appearance and color.In a first embodiment of the invention use is made of the advantages ofmicrowaves combined with the advantages of heat treatment processes suchas frying and/or cooking. The food substance such as meat and fish willbe preheated/precooked with microwaves before the next heat treatmentprocessing step such as frying and/or cooking.

In FIG. 15 a modular designed apparatus 1 designed to use in acontinuous production line comprises multiple modules, in thisembodiment six, depicted as M1-M6 and preferably connected to each otherto form a single structure, here a tunnel wherethrough the substances tobe treated are conveyed by conveyor 10, which preferably movescontinuously. The speed of the conveyor belt is preferably provided asdata to a control unit to control the treatment processes in modulesM1-M6 accordingly. M1 is the module most upstream module and M6 is themost downstream module, relative to the direction of motion of thesubstances to be treated. Advantage of such a modular design can be thatin each and every module a separate process application with uniquesettings can takes place. In another embodiment in multiple modules thesame application can take place. One of the applications is a treatmentwith microwaves generated by solid-state energy sources.

This modular design results in reduction of costs and an increasedflexibility regarding process applications.

In this embodiment formed meat substances such as burgers, nuggets,chicken wings or a food mass will be heated. Shielding means 24 canpositioned at the inlet of module M1 and/or at the outlet of module M6to prevent microwaves from coming out of the apparatus. Module M1 ishere provided with sensor means in order to determine the presence ofsubstances on the conveyor 10. This information can be used in module M2to determine when the heating process should be started. Both modules M2and M3 hear comprise solid-state RF energy sources. In module M4absorption measurements can be done to determine if the meat substancesare equal heated. In module M5 further heating will be provided to thesubstances but preferably only were need according the measurements inmodule M4; i.e. substances are individually whose temperature is toolow. Module M6 can, for example, be provided with infrared heatingmeans, particularly for boneless and flat shaped products, in order toestablish browning and/or a crispy outer layer. In a more preferredembodiment the sensing means in M1 can determine the dimensions, shapeand/or volume and/or weight of the food substance. This data can beutilized in a control unit to calculate and control an individualheating process for each and every single food substance on belt 10 orfor a row and/or column of substances on the belt.

The modules M1-M6 are preferably provided on a frame 27, more preferablyon the frame of the conveyor means 10. Preferably, the sequence of themodules M1-M6 can be changed. Each module M1-M6 and the conveyor meansare preferably connected to the same control system.

The conveyor means 10, are preferably designed such that they are atleast partially, preferably entirely transparent for the microwaveradiation.

In FIG. 16 a modular designed apparatus 1 comprises multiple modulesdesigned to use in batch production: i.e. the conveyor belt 10 movesintermittently. Reference is made to the description according to theembodiment of FIG. 15, which at least partially also apply to theembodiment according to FIG. 15. In this embodiment 6 modules depictedas M1-M6 can be used and connected to each other. A substance will besubjected to a first treatment in module M1 and when this treatment isfinished a next treatment in module M2 followed by treatments in othermodules M3-M6 can take place. The through opening, preferably the entirethrough opening above the conveyor belt 10 and between two adjacentmodules can be provided with shielding means (not shown) in order toprevent that a treatment in one of the modules will influence thetreatment in a neighboring module. Additionally or alternatively suchshielding means can be provided at the inlet of module M1 and/or at theoutlet of the module M6, for example to prevent microwaves from comingout of the apparatus. In this embodiment module M1 can provided with asensor, for example detection means 25 such as a camera system to detectwhat kind of substance is positioned at which location on the belt. Thisinformation preferably comprises the area of the substance parallel tothe conveyor, the height of the substance and/or its density and/orweight. In case the thickness changes, local thicknesses can bedetermined. This information can be used to adjust and/or control thetreatment process in the following modules M2-M6. In module M2absorption measurements can be done, for example to determine thetemperature of one or more substances on the belt. It is determined forexample, if the temperature of the substances is equal and/or thetemperature distribution of each substance. The temperature reading canbe used to control the subsequent treatment step(s). In module M3 themeat substances can be heated with solid-state RF energy sources to apredetermined temperature. In module M4 absorption measurements can bedone to determine if the mutually heated substances are all in the sametemperature range. In module M5 further heating can be provided to thesubstances, were need according the measurements in module M4. Module M6is an optional additional shielding module to prevent microwaves fromcoming out of the inventive apparatus.

In case the processes in all modules are finished the respectiveshielding means can be altered, for example tilted such that thesubstances can move from one module to another. As soon as thesubstances are shifted to the next module, shielding means can closeagain.

Regarding FIGS. 15 and 16 but also as a general teaching, a desireddistribution of the RF-energy over the width of the conveyor means ispreferred. The inventive processing apparatus therefore may comprise amultitude of solid state RF energy sources along one line and/or oneplane, which is at least essentially perpendicular to the transportationdirection of the conveyor belt. Each of these sources can preferably becontrolled individually. The energy distribution over the width may beevenly or according to a desired pattern. The energy distribution overthe width can be set according to the local load of substances on thebelt.

EXAMPLES Example 1

Reference is particularly made to the embodiments according to FIGS. 15and 16 and the other examples. Over the width of a, preferablycontinuously, running conveyor means 10 multiple substances arepositioned side by side. The temperature of these substances shall beequalized and/or raised over the width of the conveyor means 10. This ispreferably accomplished by absorption of microwave radiation provided bya solid-state RF energy source. The absorption of the microwaveradiation is preferably measured for each substance individually and/orfor a certain range of the width of the conveyor means. If needed thetemperature of one or more substances which is, for example, too low isadjust/increase by directing microwaves generated by a solid-state RFpower amplifier to the substance which has the low temperature.

Via the antenna 17 microwaves are radiate to the substances to be heatedand ingredients such as water and fat will absorb the energy.Simultaneously that part of radiation what is not absorbed by theingredients in the substance will be absorbed by the antenna and themeasured absorption will be used to control the solid-state RF energysources.

Depending on the width of the belt and the number of substancespositioned on the belt two or more solid-state elements and antennaswill be used in order to increase accuracy of the process.

Example 2

Reference is particularly made to the embodiments according to FIGS. 15and 16 and the other examples. In the present case, pre-heated foodsubstances are transported on a preferably continuously, runningconveyor means, preferably a belt, before these substances enter afurther heat treatment process such as frying or cooking. In a fryer orcooking oven the heat/energy enters the food substance from the outsideand is then transported by conduction and consequently it takes a whilebefore the desired core temperature is reached.

By pre-heating food substances with microwaves generated by solid-stateenergy sources the entire substance volume will be, within certaintolerances, heated at once and hot- and/or cold-spots can be avoided dueto control of radiation based on absorption measurement. All substancesalong the width of the conveyor means have at least essentially the sametemperature.

Result will be that the fryer or cooking oven can run with a higher linespeed (less residence time substance in fryer or oven) or less heatingcapacity in the fryer or oven is needed resulting in energy-saving.

This is a typical line application in which the inventive apparatus iscombined with another apparatus, for example a fryer and/or a cookingoven. The solid state RF energy source can be provided up- and/ordownstream from the other apparatus in the line.

Example 3

Reference is particularly made to the embodiments according to FIGS. 15and 16 and the other examples. In the present case, heat treatedsubstances, for example cooked and/or fried food substances, aretransported on a preferably continuously, running conveyor means,preferably a belt. Measuring the doneness, e.g. the core temperature ofthese substances, after treatment in the heat treatment application suchas cooking. By measuring the doneness by means of an absorptionmeasurement it can be determined if the substances are for instancefully cooked. If not, the measurement can be taken to apply the correctamount of microwave energy. The measurement of the absorption ispreferably done by means of the antenna 17.

In above embodiments microwaves generated by solid-state RF energysources are deployed to preheat, precook and/or dry food and feedsubstances before these substances are subjected to a next or final heattreatment step within a further processing line.

In different, following embodiments microwaves generated by solid-stateRF energy sources will be deployed after a previous heating, cookingand/or drying treatment. However, for the following examples, referenceis also made to the explanations according to FIGS. 1-16. The disclosuremade regarding FIGS. 17-23 also applies to the previous Figures.

FIG. 17 depicts a frying application wherein food substances first willbe par-fried followed by a microwave post-heating step with solid-stateRF energy sources. Nowadays partial frying is a common procedure toprevent food substances being too fat and will have too much calories.The substances will be fried for the shorter period of time incomparison to deep frying wherein the food substance is submerged in thefrying oil until it is entirely cooked.

In case of a coated substance during par-frying the core of thesubstance will remain unaffected e.g. un- or only little heated and/orno or little oil-absorption. Due to dehydration of the surface theMaillard reaction creates a golden brown exterior of the food substance.This dehydration will settle the coating; it forms a, preferably crispy,crust, an essentially closed layer which prevents or limits oilabsorption and prevents loss of moisture/natural juices furtherdownstream.

A par-fried food substance is not fully cooked and will be directlyfrozen after frying or the whole substance be fully cooked in a line orspiral oven or in this embodiment by microwaves generated by solid-stateRF energy sources.

In case of steam cooking, e.g. condensation cooking of uncoated foodsubstances, such as fillets, the substances can be treated withmicrowaves generated by solid-state RF energy sources either before orafter the steam cooking process. The combination of both processes willhave the benefits of steam cooking (retaining of nutrients without driedout food substances) and microwave, which can a fast process. FIG. 18depicts a steam cooking process wherein the outside of the foodsubstance will be sealed. To prevent loss of moisture by subjecting thefood substances too long to high temperatures, a microwavepost-heating/post-cooking process will be a subsequent processing step.Microwaves will not color the food products.

FIG. 19 depicts a process wherein first a substance will becolored/browned in an oven and subsequently will be post-heated withmicrowaves generated by solid-state RF energy sources.

In FIG. 20 first the food substances comprising a bone-structure forinstance wings or drumsticks e.g. from a chicken are roasted in an ovento obtain a crispy skin. Hot air can settle the coating and anessentially closed layer/crust with an attractive outside color canresult. The cooking process will be followed by post-heating withmicrowaves generated by solid-state RF energy sources.

In case of cooking substances comprising a bone structure in an oven themeat is relatively quickly cooked and colored, preferably with hot airwith a predetermined humidity via the outside of the product, howeverthe bone itself is not heated or not sufficiently heated. Due to safetyreasons (reduction of bacteria to a safe level) the bone temperatureneeds to be above a minimum temperature, for instance 84° C., muchhigher than the core temperature of the meat should be. In traditionalcooking applications the cooking process will be proceeded until thebone temperature has reached the desired correct temperature. However,the substances remain a relatively long period within the cooking ovenwhich results in cooking losses such as the loss of water, other juices,fat and salts.

In the examples according to FIGS. 19 and 20 the meat substance can forinstance be cooked in one and/or multiple zones until the temperature ofthe meat is not necessarily but preferably according to a minimumrequired temperature and/or a desired final core temperature is forinstance 72° C., for example in order to kill bacteria. In case thefinal core temperature has been reached the coloring, juiciness andcrispness will be as desired but the temperature of the bone structureis still lower as it should be.

In an embodiment of the process cooked substances will exit the oven ata temperature below the desired meat temperature and/or below thedesired bone-structure-temperature. In the next processing stepmicrowaves generated by solid-state RF energy sources can be applied tofurther heat the meat and bone structure for instance from 65° C. to 84°C. Preferably the meat temperature (core temperature) will be heatedfrom 65° C. to the desired temperature, for instance 72° C. andpreferably the bone structure will be heated to the desired temperature,for instance 84° C.

In another embodiment of the process the substances will exit the ovenwith the desired meat temperature, for instance 72° C. and in the nextprocessing step microwaves generated by solid-state RF energy sourcescan be applied to further heat the bone structure till the desiredtemperature, for instance 84° C. The food substances are subjected to arelatively short cooking time in the oven.

Simultaneously or in a next processing step the solid-state energysources can be applied to measure the temperature of the meat and/orbone-structure of the multiple food substances for example on a conveyorand in case the meat temperature or the temperature of the bonestructure of the preferably individual food substances is not accordingthe desired temperature further heating of the meat and/or bonestructure of the preferably individual food substances will be applied.Correcting the temperature of a meat substance with microwaves after thecooking oven gives the opportunity to heat the food substance within theoven just until the desired temperature which results in less cookinglosses and increased energy efficiency.

Preferably, at least one solid state RF energy source will be controlledsuch, that it specifically heats the bone structure and/or itssurrounding meat. The frequency, the amplitude, the frequency, thewavelength, the phase versus time and/or direction of radiation

and/or the radiation energy emitted by the solid state RF energy sourcecan be controlled such that the microwaves is specifically absorbed bythe bone and/or the surrounding meat, particularly the meat that has notyet reached the desired temperature. The temperature of the bone and/orthe surrounding meat is preferably monitored and the emission of thesolid state RF energy source is preferably adapted.

FIG. 21 depicts a processing line comprising frying, preferablypar-frying, a cooking step for example with steam, followed bypost-heating with microwaves generated by solid-state RF energy sources.In FIG. 22 in a first zone preferably after a short time period ofcondensation cooking the products will be subjected to convectioncooking and thereafter post-heating with microwaves.

In FIG. 23 measurement means M such as solid-state RF sources areintroduced to measure the doneness and/or status of the food substancesbetween individual heat treatments. Preferably the doneness measurementwill be the base for controlling the previous and/or following heattreatment processes. Measurement means M will not necessarily butpreferably positioned before/after and between each and every heattreatment process and in an even more preferable embodimentwithin/during each and every heat treatment process. The measurement ofthe doneness preferably includes the measurement of a bone structure, incase the substance comprises a bone structure.

Besides preheating, precooking, drying, post-heating and post-cookingmicrowaves generated by solid-state RF energy sources can also beapplied further upstream, preferably before the substances entering afurther processing line or at least before the substances will besubjected to heat treatment within the further processing line. Aim isto heat the bone structure and/or, depending on the application,combined with limit heating of the meat.

In a traditional process of processing substances comprising abone-structure, for instance coated drumsticks or coated chicken wings,first the coating will be applied, then the substance will be par-friedsuch that the coating will be settled and in a next step the substancewill be finally cooked in an oven. However, when dealing in particularwith frozen young chickens/broilers the surface of the bone and adjacentmuscle tissues can become colored after cooking due to leakage of bonemarrow.

The chickens we eat today are between six and eight weeks old and haveunder developed more porous bones than older chickens. When youngchickens/broilers are frozen liquids in the mass of chicken includingbone marrow will expand. The bone marrow inside of chicken bones ispurplish and can permeate through the porous chicken bones as it expandsand forms ice crystals. These ice crystals further break down the bonestructure. When heating/cooking the purple marrow in the bones seepthrough the porous bones and leaks into the meat. The surface of thebones and the adjacent meat become deep red/purple or even black.

In an embodiment of the invention the leakage of bone marrow can bestopped by coagulate the marrow within the bones by using microwavesgenerated by solid-state RF energy sources. The temperature willpreferably be in the range of 50° C. till 80° C., more preferably 50° C.till 70° C. The settings such as power level, frequency, wavelength,phase versus time, amplitude, magnitude of radiated power and/ordirection of radiation will be optimized to penetrate the chicken meat,bone structure and to treat bone marrow. The treatment of substancescomprising a bone-structure with microwaves will be applied before thesubstances are subjected to a heat treatment process such as frying andcooking, preferably the treatment will be applied before the freshchicken bone-structure containing substances will be frozen. The processto minimize/stop leakage of marrow is not limited to chickenbone-structure comprising substances but is also applicable for otherbone-structure containing substances such as beef, lamb, pork, poultryin general. The status of coagulation of proteins and starch will bedetermined by absorption measurements with solid-state RF energysources. The status can be determined by comparing the measured resultswith the known and in the control system implemented absorption curve ofboth non-coagulated proteins and starch and entirely coagulated proteinsand starch.

Particularly regarding FIG. 24, in prior art applications with coating,preferably crumb coatings and particular with fine flour coatings manyparticles will loosen from the food product and enter the oil bath. Theresult is loss of coating material and food material and despitefiltering the frying oil the lost material results in degradation of thefrying oil and consequently in decrease of the shelf life of the oil.

This problem is solved with the embodiment according to FIG. 24, whichdepicts an embodiment wherein solid-state RF energy source(s) is/areapplied between the coating 31 and frying 4. In an embodiment of theinvention the batter will be stabilized in order to improve the bindingof the coating (flour, crumbs, etcetera) to the food product. Preferablythe coating is set, stabilized and/or improved by a treatment 32 withsolid-state RF energy sources, preferably by introducing the correctsettings such as frequency, phase versus time and/or amplitude. In thepresent example, the food products enter the preferably continuousfryer. Due to the already set coating less coating material and foodmaterial will be lost inside the fryer resulting in the increase of theoperating time of the frying oil. By (par) frying the products willbecome the correct taste, smell and color. In case the surface and/orcore temperature of the products are increased by microwaves the fryingprocess can be shortened.

FIG. 25 is similar to FIG. 24 with the difference that (par) frying willbe followed by cooking. Reference is made to the disclosure according toFIG. 24.

FIG. 26 shows an embodiment of a continuous processing line comprising acoating step 31 followed by a step wherein the surface of food productswill be provided with edible oil 31 by spraying oil on the productsurface. Curtains of oil flowing over the product or creating a mist ofoil around the product can also be seen as spraying. By spraying oilless mechanical impact will be subjected to the food products compare toa continuous fryer and the coating will remain intact. In a nexttreatment the products will be cooked in an oven, preferably byconvection or impingement the coating will be set. To preventdifferentiation between the upper part and bottom part of the foodproduct heat treatment such as condensation and/or convection and/orimpingement will preferably take place from above and from below theproduct.

Regarding FIG. 27, in the state of the art the food products will becoated with a coating comprising edible oil and thereafter cookedwithout being fried in a fryer. In a multiple zone oven the productswill be subjected shortly to condensation cooking and for a longer timeperiod to convection cooking within a first zone in order to set thecoating. In a second zone the products will be colored/browned. Theresults such as a crispy outer layer, taste and browning of the finalproducts depends mainly on the content of oil within the coating.

Field experience learns that oil content in the currently availablecoatings is often critical low. To improve this more oil should besupplied to the food product. FIG. 27 depicts an improved embodimentwherein products provided with a coating 31 comprising edible oil firstwill be sprayed with oil 33 and finally will be cooked in an oven. Toprevent differentiation between the upper part and the bottom part ofthe food product the spray unit should not only spray additional oilfrom above but also from the sides and from below the food product.

Solid-state RF energy sources to generate microwaves are implemented inthe embodiment of FIG. 27 as depicted in FIG. 28. Microwaves can beapplied to preheat/precook 5 the products and/or to set the coating 32,preferably fast. A suitable position of solid-state RF energy sourceswill results in a correct treatment of the side parts and bottom part ofthe food product. The method depicted in FIG. 26 can also be followed bySolid-state RF energy sources to generate microwaves

In FIG. 29 the treatment steps are reversed such that products coatedwith a coating comprising oil 31 will first be treated by microwavesgenerated by solid-state RF energy sources, for instancepreheated/precooked 5 and/or the coating will be set 32. After thistreatment the products will be sprayed with edible oil 33 followed bycooking.

FIG. 30 depicts the inside of a microwave processing apparatus 1 able totreat food products with microwaves generated by solid-state RF energysources. Food products 11 enter the apparatus at inlet 21 and leave theapparatus at outlet 20. As a result of heat treatment with microwaves,moisture 34 will be released from the food products, to prevent a wetbottom side of food products this released moisture must be able toescape and therefor conveyor belt 10 should be open, for exampleprovided as chains or a mesh. Air flow 36 can be introduced in order toforce the removal of moisture. Drip collection means 35 can collect anddischarge the released moisture. Openness and material of conveyor belt10 should be such that the conveyor structure and material will notinfluence the heating process and/or absorption measurement.

This embodiment is not limited to non-coated food products but is alsoapplicable for all kind of coated products.

Regarding FIG. 31a, b , linear ovens or spiral cooking ovens known fromthe state of the art comprising a first chamber/zone 29 with a linear orspirally-wound belt, preferably a second impingement zone 30 and a thirdchamber/zone 22 with a linear or spirally-wound belt. Products, such asmeat products, will first be treated in the first zone 29 depending onthe product to be treated with condensation cooking orcondensation/convection cooking. During condensation cooking moistureand free water will condense on the surface of the food productresulting in a phase change of the steam resulting in energy deliveredto the surface of the product. The temperature difference betweensurface temperature and core temperature is at the start of the processrelatively large and the heat will transfer from the surface to the corepreferably by conduction.

At a certain moment, when wet bulb temperature is reached, the rise oftemperature stops/stalls despite supplying energy to the meat products.This temperature stall is the point when the product temperature hasreached the wet bulb temperature and is caused by evaporative cooling.The time period of the stall is determined by the free moisture from themeat and from the marinade in case the product is marinated. This freemoisture is evaporating from the pores and cells and consequently coolsdown the meat. As the temperature of cold meat rises, the evaporationrate increases unit the cooling effect balances the heat input. Thestall stops when “unbound free water” from the surface and just below isreleased.

The cooking process will be continued in the oven in preferably animpingement zone with high air temperature directed with high speed tothe surface of the product succeeded by a convection zone with increasedtemperature to for instance brown the products. During cooking both thesurface and core temperature will follow a line. During the stall thisline slopes down and after the stall the line follows the originalcurve. The thermal conductivity of the food product determines howquickly the temperature difference between surface and core can bereduced, this parameter cannot be changed.

FIG. 31a depicts a double spiral oven known from the state in the arthowever extended with optional measurement means M. FIG. 31b is asimilar embodiment as FIG. 31a with the difference that this embodimentis particularly directed to the use of coatings comprising oil. In afirst zone mainly convection cooking will take place, in an optionalsecond zone the products will be subjected to impingement and in a thirdzone convection cooking to color/brown the products. The measurementmeans measure the temperature of the product prior to entering the ovenand/or after the first zone and/or at the exit of the oven. Based on atleast one of these measurements, a controller can adjust the temperatureand/or humidity and/or steam- and/or fresh air injection into the oven.

Regarding FIG. 32a, b , in an embodiment of the invention the productsare subjected to microwaves generated by solid state RF energy sourcesbefore the products enter the cooking oven. Microwaves heat up theproduct homogenously and the core temperature rises relatively fast withless temperature difference between surface and core. The surface andcore temperature of the food product are influenced without beingrestricted by the thermal conductivity product parameter. The productswill enter the cooking oven with a higher surface temperature andparticular a higher core temperature, consequently while the surfacetemperature will be reached sooner the time period of condensationcooking with steam will be shorter and advantageously less free waterwill be at the products.

Less free water will decrease the period of the evaporative cooling anda shorter period of stall thereby increasing the (energy) efficiency ofthe cooking process.

In another embodiment of the invention depicted by FIG. 32a nopreheating with microwaves generated by solid-state RF energy sourceswill take place. In the first zone 29 food products will be subjectedmainly to condensation cooking. In a second optional zone the foodproducts will be subjected to impingement 30 with high air temperaturedirected with high speed to the surface of the product. In a third zone22 the products will be subjected to convection cooking to achieve thecorrect crispness and to brown the products to the correct color.

Solid-state RF energy sources will be positioned within the oven to beable to direct microwaves to the food products. These energy sources canbe positioned just after the products enter the oven to be able toincrease the surface temperature and/or the core temperature at an earlystage, and/or somewhat further in the oven to boost mainly the coretemperature of the food products.

In a different embodiment these energy sources will be positioned,preferably alternatively or additionally, just after the location in theoven where the stall is reached. Microwaves will then increase the coretemperature of the product.

In a further embodiment energy sources will be positioned, preferablyalternatively or additionally, in for instance in the second and/orthird zone. Multiple solid-state RF energy sources can be positioned indifferent locations within the oven to be used for different tasksand/or combinations of tasks. Applying microwaves directed bysolid-state RF energy sources will shorten cooking time and/or increasethe oven capacity.

FIG. 32b is a similar embodiment as FIG. 32a with the difference thatthis embodiment is particularly directed to the use of coatingcomprising oil. In a first zone mainly convection cooking will takeplace, in an optional second zone the products will be subjected toimpingement and in a third zone convection cooking to color theproducts.

In a further embodiment condensation cooking respectively convectioncooking will be applied to heat the food product from the outside to theinside and will be combined with microwaves generated by solid-state RFenergy sources mainly to boost the core of the food product.

The described use of solid-state RF energy sources is also applicable toa spiral oven consisting of one zone and a linear oven consisting of oneor multiple zones.

For all applications described in this document the combination ofmultiple frequencies can be applied. For instance a low frequency ofapproximately 915 MHz for heating up thicker blocks of food mass betweensurface and core of the product and a higher frequency to direct heatonly to the outside surface of the food product. Multiple frequenciescan be generated by one solid-state RF energy source but preferablygenerated by multiple solid-state RF energy sources wherein each andevery solid-state energy source will generate a certain programmedfrequency. Preferably solid-state RF energy sources generating differentfrequencies are within the heating apparatus located in differentproduct chambers.

A step with a higher frequency than 2450 MHz generated with solid-stateRF energy sources, preferably between 3 GHz and 300 GHz, can be directedto the outside of the product. Less penetration depth will onlydehydrate the surface of the food product to create a Maillard reactionresulting in a golden brown exterior of the food substance. Preferablythe browning will take place over the entire surface area of theproduct, therefor one or more energy sources will be used. The controlunit will adjust the phase change in order to achieve a controlledbrowning around the entire surface.

For instance a bone-in product as drumsticks can be treated with afrequency of 2450 MHz to heat up the product between the surface andcore of the product and a higher frequency only directed to the surfaceof the product in order to create a Maillard reaction.

The processes described above are not limited to meat substances but arealso applicable for fish, vegetarian substances, vegetables, pet food,etcetera.

The processes described above are not limited to a process step withmicrowaves generated by solid-state RF energy sources before a fryerand/or cooking oven or a process step with microwaves generated bysolid-state RF energy sources after a fryer and/or cooking oven. Thecombination of a process step with microwaves generated by solid-stateRF energy sources before and after a fryer and/or cooking oven and/oranother heat treatment process is also applicable.

The use of measurement means and/or the combination of measurement meanssuch as absorption measurement by solid-state sources, donenessmeasurement by using solid-state sources and detection means 25 such ascameras are not limited to one of the Figures above.

For all embodiments and all examples provided above measuring/detectionmeans 25, such as cameras, can be provided to be able to detect/identifythe position and/or type and/or shape and/or weight and/or volume and/ordensity and/or dimensions and/or color of the food product/mass.

Measuring/detection means such as cameras can be provided in order todetect/identify the belt load and the position and variation ofproducts/mass.

Measuring/detection means such as thermal imaging cameras can be used inorder to control the temperature within the process. These measurementsare non-contact temperature measurements and can be used to measure thedoneness/if food products are well cooked as well as in an oven as inthe microwave.

The measuring/detection means such as cameras can be positionedbefore/at the entrance of a heat treatment process such as an oven inorder to be able to adjust the parameters of the cooking process, thecameras can be positioned further downstream for instance in an oven todetect/identify the status of the process and successively theinformation can be used by the control unit to adjust relativeparameters. The measuring/detection means can be positioned after thefor instance heat treatment process in order to check if the productsare well cooked. In a preferred embodiment the measuring/detection meanssuch as cameras will be able to detect/identify relevant parameters ofeach and every food product such that particularly when usingsolid-state RF energy sources each and every food product can be treatedseparately. In case for instance the volume and type of the foodsubstances is determined the control unit is able to calculate the heattreatment process parameters.

The measuring/detection means such as cameras will be used able tohandle conveyor means with multiple lines with substances but also beable to handle conveyor means with random oriented food substances. Whenusing solid-state RF energy sources the control unit is able todetermine at which time which energy source will be activated based onamongst others the speed of the conveyor.

LIST OF REFERENCE SIGNS

-   1 processing apparatus, microwave apparatus, heat treatment    apparatus-   2 solid-state RF energy source-   3 solid-state RF energy source microwave heating-   4 frying-   5 solid-state RF energy source microwave heating    precooking/preheating-   6 cooking final cooking-   7 solid-state RF energy source microwave heating drying-   8 housing-   9 inner wall housing 8-   10 conveyor means, conveyor, conveyor belt-   11 product, food product, substance-   12 browning-   13 solid-state RF energy source microwave drying-   14 product chamber, cooking chamber-   15 roasting-   16 waveguide-   17 antenna-   18 cooling chamber-   19 smoking-   20 outlet, exit-   21 inlet-   22 convection cooking-   23 microwave transparent shielding means-   24 shielding means-   25 detection means, camera-   26 radiation treatment, grilling, infrared treatment-   27 frame-   28 steam cooking-   29 condensation cooking-   30 impingement-   31 coating-   32 solid-state RF energy source microwave to set coating-   33 spray with edible oil, curtains of edible oil, mist of edible oil-   34 drip, moisture-   35 drip collection means-   36 air flow-   M measurement means, doneness measurement, microwave doneness    measurement-   M1-6 modules

1. A line for heating, drying, cooking, disinfecting, pasteurizingand/or sterilizing a substance with an apparatus comprising at leastone, solid-state radio frequency sources and a further heat- orcold-treatment apparatus.
 2. The line according to claim 1, wherein theapparatus is connected by a conveying means.
 3. The line according toclaim 1, the solid-state radio frequency source is provided in an arrayof n columns and m rows, wherein n is an integer >1 and m is an integer≥1.
 4. The line according to claim 1, wherein the solid-state radiofrequency source is provided equidistantly around a circumference of aproduct chamber.
 5. The line according to claim 3, wherein the columnsextend around a conveyor belt.
 6. The line according to claim 2, whereinat least a section in which the solid-state radio frequency source isprovided is shielded.
 7. The line according to claim 1, wherein: asolid-state RF energy source microwave preheating step is followed by afrying-step or vice versa, and/or a solid-state RF energy sourcemicrowave precooking step is followed by a cooking-step or vice versa,and/or a solid-state RF energy source microwave drying step is followedby a browning-step or vice versa, and/or solid-state RF energy sourcemicrowave drying step is followed by a roasting-step or vice versa,and/or solid-state RF energy source microwave drying step is followed bya smoking-step or vice versa, and/or a frying step is followed by asolid-state RF energy source microwave precooking step, which isfollowed by a browning and/or roasting and/or smoking and/or radiationstep or in a different sequence, and/or a solid-state RF energy sourcemicrowave batter stabilizing step is followed battering step, isprovided.
 8. The line according to claim 1, wherein the solid-state RFenergy source and a convection cooking means are provided in onehousing, and are connected by conveyor means.
 9. The line according toclaim 1, wherein the line comprises a means to measure doneness.
 10. Theline according to claim 9, wherein the measure of the doneness isexecuted with the solid-state radio frequency energy source.
 11. Theline according to claim 1, wherein the substance comprises abone-structure, wherein the at least one solid-state radio frequencysource is controlled to specifically heat the bone-structure and/or meatsurrounding the bone-structure.
 12. A method for heating, drying,cooking, disinfecting, pasteurizing and/or sterilizing a substance withan apparatus comprising at least a solid-state RF energy sourcemicrowave heating step and a further heat treatment step.
 13. A methodfor heating, drying, cooking, disinfecting, pasteurizing and/orsterilizing a substance with an apparatus comprising a heat treatmentstep and a post heating with at least a solid-state RF energy sourcemicrowave heating step.
 14. The method according to claim 12, whereinparameters of the substance are inputted into a control system and acontrol unit sets the parameters at least for the solid-state RF energysource microwave heating step accordingly.
 15. The method according toclaim 12, wherein the substance comprises a bone-structure, wherein thepost heating is adapted to specifically heat the bone-structure.
 16. Themethod according to claim 12, wherein the solid-state radio frequencysource is utilized to measure doneness of the substance.
 17. The methodaccording to claim 12, wherein parameters of the further heat treatmentstep or a post heating step are controlled by the control unit.